Gasoline fuel



United States Patent Ofiice 2,833,635 Patented 'May 6, 1958 GASOLINE FUEL Eugene F..Hill, Birmingham, and David 0. De Pree, Royal Oak, Mich., assignors to Ethyl Corporation, New York, N. Y., a corporation of Delaware No Drawing. Application April 29, 1954 Serial No. 426,568

14 Claims. (Cl. 44-69) This invention relates to improved fuel for internal combustion engines and to composite additives for such fuel.

This application is a continuation-in-part of our copending application, Serial Number 336,634, filed February 12, 1953, now abandoned.

Erratic ignition produced by glowing engine deposits is currently a severe problem in the spark ignition type internal combustion engine. This phenomenon known in the art by a variety of terms such as pre-ignition, autoignition, deposit-induced autoignition, wild ping, etc., manifests itself in reduced efliciency of operation, loss of power and fuel economy and in increased wear of engine parts.

Gasoline additives suggested heretofore to obviate this problem have been more or less effective.

However,

those of suflicient effectiveness have suffered from other drawbacks. Chief among these are the characteristics of promoting TEL destruction and decreased exhaust.

valve life. The art appreciates that antagonism toward tetraethyllead not only is economically wasteful but results in loss of octane quality of fuel, a characteristic especially desired in these days of the high compression engine. Reduced exhaust valve life, which is especially prevalent under heavy duty operating conditions, is expensive and necessitates frequent engine overhauls. Even during operation the loss of compression because of burned or worn valves results in loss of power and of fuel economy. Therefore, the need exists for a means of reducing deposit-induced autoignition without incurring substantial loss of either tetraethylleadeffectiveness or exhaust valve life.

An object of this invention is to provide composite additives for internal combustion engine fuel capable of reducing substantially autoignition with a minimum of organolead antagonism and freedom from substantial loss of exhaust valve life. Another object is to provide improved fuel for spark ignition internal combustion engines having the above desirable attributes. Other important objects of this invention will be apparent from the ensuing description.

The above and other objects are accomplished by providing a composition adapted for use as an additive for spark ignition internal combustion engine fuelcomprising a hydrocarbon lead compound and a phosphonitrilic halide having from 3 to 4 atoms of phosphorus per molecule, the phosphorus-to-lead atom ratio being from about 0.0067 to about 0.67. In other words, we employ from about 0.01 to about 1.0 theory of phosphorus in our composite additives, a theory of phosphorus being the quantity required to react with the lead to form lead ortho phosphate, or two atoms of phosphorus per each three atoms of lead. Composite additives falling within the above range of proportions are capable of (1) obviating ordinary knock, (2) reducing deposit-induced autoignition, and (3) controlling to a degree the amount of deposits formed in the engine. These benefits are obtained with a minimum of organolead destruction and reduced exhaust valve life.

We prefer to use organic halogen-containing compounds (ethylene dibromide and/or ethylene dichloride, etc.) in our antiknock fluids as this affords a greater degree of scavenging action, particularly of exhaust valves, without interfering with the anhanced autoignition sup pressing properties we have provided. Thus, in another of its forms this invention embraces a composition adapted for use as an additive for spark fired internal combustion engines consisting essentially of a hydrocarbon lead antiknock compound, organic halogen-containing material present in amount suflicient to effectively reduce the amount of deposits formed in the engine, and, in quantity suflicient to reduce autoignition, a hosphonitrilic halide having from 3 to 4 atoms of phosphorus per molecule.

This quanity as above stated is from about 0.01 to about 1.0 theory of phosphorus.

Dyes, antioxidants, corrosion inhibitors, anti-rust and anti-icing agents, solubilizers such as kerosene and the like may also be present in our antiknock fluids.

Superior fuels of this invention are provided when our above antiknock fluids are blended in antiknock quantities with hydrocarbon fuel of the gasoline boiling range. Amounts of lead up to 6.3 grams per gallon of fuel can be used. Thus,in the case of tetraethyllead there can be present up to about 6.0 milliliters per gallon of gasoline. Greater or lesser concentrations of hydrocarbon lead compounds may be employed depending upon the nature of the base fuel and the type of service to be encountered.

Phosphonitrilic halides are prepared by methods known in the art. For example, phosphonitrilic chlorides may be prepared by passing gaseous ammonia over phosphorus pentachloride followed by steam distillation. It is preferable, however, to prepare these materials by reacting ammonium chloride with phosphorus pentachloride at a temperature between about and about 200? C. followed by solvent extraction, fractional or steam distillation or the like. Solvents such as tetrachloroethane may also be used in this process. Modifications of these processes to obtain other phosphonitn'lic halides such as the fluorides, bromides, and mixed halogen-containing compounds are reported in the literature.

Phosphonitrilic halides containing from 3 to 4 atoms of phosphorus in the molecule are generally considered to be cyclic compounds having the formulae Trimeric hogphonltrilic Tetrameric phosphonitrilic halide phonitrilic chloride, tri-dibromophosphonitrilic iodide,

tri-difluorodibromophosphonitrilic chloride, tri-dichlorohosphonitrilic fluoride; and the tetrameric forms, viz, tetrahosphonitrilic chloride, tetrahosphonitrilic bromide, tetrahosphonitrilic iodide, tetra-tetrafluorophosphonitrilic chloride, tetra-difiuorophosphonitrilic bromide,

EXAMPLE I To 330 parts of tetraethyllead is added 15.8 parts of tri-phosphonitrilic chloride. After mixing the anti-knock fluid contains 0.2 theory of phosphorus.

EXAMPLE II The procedure described in Example I is repeated using 39.4 parts of the phosphorus compound. The resulting composite additive contains 0.5 theory of phosphorus.

EXAMPLE III 14.7 parts of tri-phosphonitrilic chloride was added to 309 parts of tetraethyllead as an antiknock fluid consisting essentially of tetraethyllead, 1.0 theory of bromine as ethylene dibromide and a minor amount of kerosene and dye, the percentage composition of the original fluid be ing tetraethyllead,'61.41 percent, ethylene dibromide 35.67 percent, and dye and kerosene 2.92 percent. On mixing, the improved antiknock composition contained 0.2 theory of phosphorus; The blue dye remained visably un affected.

EXAMPLE IV 73.4 parts of tri-phosphonitrilic chloridewas mixed with 618 parts of tetraethyllead as an antiknock fluid as described in Example III. The resulting fluid contained 0.5 theory of phosphorus. No change in the dyestuff was noted.

EXAMPLE V 3.9 parts of tri-phosphonitrilic chloride is added to 165 parts of tetraethyllead as an antiknock fluid consisting essentially of 61.48 percent tetraethyllead, 17.86 percent ethylene dibromide, 18.81 percent ethylene dichloride, and 1.85 percent of dye and kerosene. After mixing the fluid contains 0.1 theory of phosphorus, 0.5 theory of bromine as ethylene dibromide, ,and 1.0 theoly of chlorine as ethylene dichloride.

EXAMPLE v1 The procedure ofExample V is repeated with the exception that 4.2 parts of tri-phosphonitrilic bromide is used as the phosphorus compound. The finished fluid contains 0.1 theory of phosphorus as this compound.

EXAMPLE VII 3.9 parts of tetra-phosphonitrilic chloride is mixed with 165 parts of tetraethyllead as an antiknock fluid comprising tetraethyllead (61.47 percent), and ethylene dibromide (35.67 percent). The fluid formed contains 0.1 theory of phosphorus.

EXAMPLE VIII In a suitable container is placed 66,600 parts of an aviation fuel of grade 115/ 145 according to ASTM specification D-910-48T. To this is added .165 parts of tetraethyllead as a conventional aviation antiknock fluid comprising tetraethyllead and one theory of bromine asethylene dibromide. 4.2 parts of tri-phosphonitrilic bromide is then added to the fuel and on mixing it contains 0.1 theory of phosphorus and approximately 4.5 milliliters of tetraethyllead per gallon.

EXAMPLE IX The procedure of Example VIII is repeated withv the exception that the base fuel :is grade 100/130 according to the above ASTM specification and 8.5 parts of triphosphonitrilic bromide is used as the phosphorus additive. The finished fuel containing approximately 4.5 milliliters of tetraethyllead .per gallon has a phosphorus content of 0.2 theory.

EXAMPLE X To 100,000 parts of a commercial motor gasoline (a blend of straight run, catalytically cracked and polymer blending stocks) containing 165 parts of tetraethyllead as an antiknock fluid having a composition of tetraethyllead 61.48 percent, ethylene dibromide 17.86 percent, ethylene dichloride 18.81 percent, and dye and kerosene 1.85 percent, is added 7.9 parts of tri-phosphonitrilic chloride. After agitating this mixture the resulting fuel contains 3.0 milliliters of tetraethyllead per gallon and has a phosphorus content of 0.2 theory.

EXAMPLE XI Using a substantially paraffinic automotive gasoline the procedure of Example X is repeated except that 7.9 parts of an equimolar mixture of triand tetra-phosphonitrilic chlorides is used as the phosphorus additive. The fuel so formed contains 0.2 theory of phosphorus.

EXAMPLE XII In a suitable container is placed 150,000 parts of a commercial blend of straight run and catalytically and thermally cracked stocks containing 2.0 milliliters of tetraethyllead per gallon as standard motor mix fluid (61.48 percent tetraethyllead, 17.86 percent ethylene dibromide, 18.81 percent ethylene dichloride, and 1.85 percent dye and kerosene). To this fuel is added 19.7 parts of triphosphonitrilic chloride. On mixing the finished fuel contains 0.5 theory of phosphorus.

EXAMPLE XIII 165 parts of tetraethyllead as an antiknock fluid consisting essentially of tetraethyllead 63.30 percent, ethylene dibromide 25.74 percent, ethylene dichloride 8.72 percent, and dye and kerosene 2.24 percent is mixed with 100,000 parts of a commercial gasoline containing straight run and catalytically cracked blending stocks. To this fuel containing approximately 3.0 milliliters of tetraethyllead per gallon is added 3.9 parts of tri-phosphonitrilic chloride. After agitation the finished fuel contains 0.1 theory of phosphorus.

EXAMPLE XIV To 100,000 parts of a blend of naphthenic and parafiinic gasoline base stocks is added 165 parts of tetraethyllead as an antiknock fluid comprising tetraethyllead, 0.5 theory of bromine as mixed dibromotoluenes and 1.0 theory of chlorine as mixed trichlorobenzenes and 7.9 parts of triphosphonitrilic chloride. After mixing the fuel contains 3.0 milliliters of tetraethyllead per gallon and 0.2 theory of phosphorus.

EXAMPLE XV 200 parts of tetramethyllead is added to 100,000 parts of a blend of straight run, catalytically cracked and polymer blending stocks. To this fuel is added 58 parts of tri-phosphonitrilic chloride. The finished fuel contains approximately 1.0 theory of phosphorus.

The foregoing examples are illustrative of the antiknock fluids and fuels provided by this invention. In those cases where conventional organic halogen-containing material has been omitted the halogen of the phosphonitrilic halides acts as scavenger.

Our improved fuels are capable of reducing the rate of wild ping otherwise occurring in an internal combustion engine by as much as percent or more. For example, a commercial automotive gasoline containing 3 milliliters of tetraethyllead per gallon as a conventional antiknock mixture produced wild pings per hour of operation of a spark ignition engine. When the same leaded fuel was treated. with one theory of phosphorus as an equialsaaeas molar mixture of tri-. and tetra-phosphonitrilic chlorides there were but 11 wild pings perhour of engine operation. rate of wild ping by 92 percent. Similarly, a fuel containing 0.2 theory of phosphorus as tri-phosphonitrilic chloride reduced wild ping by over 70 percent of base line. Equally good results are obtained from other aviation and automotive gasoli-nes of this invention.

The fuels of this invention are also capable of alleviating. spark plug fouling especially under retarded spark conditions.

In addition to, controlling erratic deposit-induced autoignition and spark plug fouling, the fuels of this invention provide other important benefits. One of these is the low degree of organolead antagonism encountered in an operating engine. By way of example, typical fuels containing different concentrations of tetraethyllead as an antiknock fluid comprisingtetraethyllead, 0.5 theory of bromine as ethylene dibromide and 71.0 theory of chlorine as ethylene dichloride, and containing 0.2 theory of phosphorus as tri-phosphonitrilic chloride were subjected to the Standard ASTM Motor Method, Test Procedure D-357 49 (which can be found inthe 1952 edition of ASTM Manual of Engine Test Methods for Rating Fuels). As a comparison the same concentrations of tetraethyllead were employed in the same fuel containing 0.2 theory of phosphorus as tributyl phosphite, an additive suggested heretofore. The results of these tests are shown in the following table:

Table Percent TEL Effect Remaining Additive lmLTEL/ 3ml.TEL/ gal. gal.

Tri-phosphonitrilic chloride 97 98. 5 Trlbutyl phosphite 92 91. 5

- a. fieet of modern high compression ratio V-8 automo- Thus, a typical fuel of" this invention reduced the biles was operated under a heavy duty schedule under controlled high speed driving conditions. The base lines for these tests were obtained with a commercial fuel containing 3.0 milliliters of tetraethyllead per gallon as a conventional antiknock fluid containing both ethylene dibromide and ethylene dichloride. The vehicles were operated under the above conditions until two exhaust valve failures were detected. In general, it was found that an average of 11,150 miles of severe driving was required for two exhaust valve failures. The test fuels were then modified such that they contained 0.2 theory of phosphorus as tri-phosphonitrilic chloride. Under the same operating conditions two exhaust valve failures occurred after an average of 9,370 miles. Thus, under adverse conditions our fuels reduced exhaust valve life by only 16 percent. An identical concentration of phosphorus as tricresyl phosphate reducedv exhaust valve life by 42 percent. In other words, the fuels of this invention resulted in a 45 percent greater exhaust valve life under heavy duty operating condition than fuels containing a phosphorus additive not of this invention.

Some of the advantages of our invention may be obtained with other inorganic phosphonitrilic compounds. Thus, recourse may be had to alkali metal salts of triand tetra-phosphonitrilic acids such as the trilithium salt of tri-phosphonitrilic acid. Although still less desirable because of instability, certain organic substituted phosphonitrilic compounds may be used. Of this type of compound the most useful appear to be the nitrogen-bonded compounds formed by reacting phosphonitrilic halides with active hydrogen-containing amines. Similar reac tion products maybe obtainable from alcohols, thiols, phenols, thiophenols or their alkali metal salts, and the likel 'A wide variety of organic halogen-containing materials can be used as corrective agents or scavengersi-nour' compositions. For example, scavengers such as dis closed in U. S. Patents 1,592,954; 1,668,022; 2,364,921; 2,398,281; 2,479,900; 2,479,901; 2,479,902; 2,479,903; and 2,496,983 can be used.

The hydrocarbon lead antiknock agents we use include lead alkyls such as tetramethyllead, tetraethyllead, tetrapropyllead, dimethyldiethyllead, trimethylethyllead, and lead aryls such as tetraphenyllead. Halogen-containing compounds such 'as triethyllead bromide may also be used.

Our antiknock fluids may be used in a variety of hydrocarbon base stocks. Thus, improvements can be made in fuels resulting from thermal and catalytic cracking processes, reforming, hydroforming and alkylating procedures and the like.

The fluids and fuels of this invention can contain conventional amounts of antioxidants such as alkyl phenols, amino phenols, phenylenediamines, etc.; corrosion inhibitors; anti-rust and anti-icing additives; dyes; upper cylinder lubricants; induction system cleanliness agents; and the like.

We claim:

1. A composition adapted for use as an additive for spark ignition internal combustion engine fuel consisting essentially of a lead alkyl antiknock agent and a phosphonitrilic halide having from 3 to 4 atoms of phosphorus per molecule, said phosphonitrilic halide being present in amount such that the phosphorus-to-lead atom ratio is from about 0.0067 to about 0.67.

2. A composition adapted for use as an additive for spark ignition internal combustion engine fuel consisting essentially of a lead alkyl antiknock agent, a scavenging amount of organic halide scavenger capable of reacting with the lead during combustion in a spark ignition internal combustion engine to form volatile lead halide, and

" a phosphonitrilic halide havingfrom 3 to 4 atoms of phoscombustion engines which consists essentially of hydrocarbon fuel of the gasoline boiling range containing up to 6.3 grams of lead per gallon as a lead alkyl antiknock agent and a phosphonitrilic halide having from 3 to 4 atoms of phosphorus per molecule, said phosphonitrilic halide'being present in amount such that the phosphorusto-lead atom ratio is from about 0.0067 to about 0.67.

6. A fuel adapted for use in spark ignition internal combustion engines Which consists essentially of hydrocarbon fuel of the gasoline boiling range containing up to 6.3 grams of lead per gallon as a lead alkyl antiknock agent, a scavenging amount of organic halide scavenger capable of reacting with the lead during combustion in a spark ignition internal combustion engine to form volatile lead halide, and a phosphonitrilic halide having from 3 to 4 atoms of phosphorus per molecule, said phosphonitrilic halide being present in amount such that the phosphorus-to-lead atom ratio is from about 0.0067 to about 0.67.

7. A fuel adapted for use in spark ignition internal combustion engines which consists essentially of hydrocarbon fuel of the gasoline boiling range containing up to about 6.0 milliliters per gallon of tetraethyllead, a mixture of bromo and chlorohydrocarbon scavengers in amount sufficient to etfe'ctively reduce the amount of de- -7 posits formed in the engine}, and a phosphonitrilic halide being present in amount such that the phosphorus-to-lead atoni'ratio is from ab611t10.0067to about 067. i

8. The composition of claim '7 in which sai'clmixture of. bromo and chlorohydrocarbon scavengers isa mixture of ethyleneidib'romide and ethylene dichloride.

9; The composition of claim 7 in which saidphosphonitrilic halide is tri-phosphonitrilic chloride,

10. The composition of claim 6 in which said phosphonitrilic halide contains three atoms of phosphorus in the molecule.

11. The composition 'of claim 6 in which said phosphonitrilic halide is tri phosphonitrilic chloride.

12..A fuel adapted for use in spark ignition internal combustion engines which consists essentially of gasoline containing up to about 6.0 milliliters per gallon of tetraethyllead, about 0.5 theory of bromine as ethylene dibromide, about 1.0 theory ofchlorine as ethylene dichloride, and a phosphonitrilic halide having from 3 to 4 atoms of phosphorus per molecule, said phosphonitrilic halide beingpresent in amount such that. the phosphorusto-lea'd atom ratio is from about 0.0067 to about 0.67. e 13. The composition of; claim 12 in. which said phosphonitrilic halide is ti'i-phbsphonitrilic chloride. f

; 14'. A fuePadapted for'use'in spark ignition internal combustion engines which consists essentially of gasoline containingup to about 3.0 milliliters per gallon of tetraethyll'ead,'about 0.5 theory of bromine as'ethylene dibromide, about 1.0 theory of chlorine as ethylene dichloride and ti'i-phosphonitrilic chloride present inamount such that the phosphorus-to-lead atom ratio is' about 0.13.

ReferencesCited in the file of this patent UNITED STATES PATENTS 

5. A FUEL OF ADAPTED FOR USE IN SPARK IGNITION INTERNAL COMBUSTION ENGINES WHICH CONSISTS ESSENTIALLY OF HYDROCARBON FUEL OF THE GASOLINE BOILING RANGE CONTAINING UP TO 6.3 GRAMS OF LEAD PER GALLON AS A LEAD ALKYL ANTIKNOCK AGENT AND A PHOSPHONITRILIC HALIDE HAVING FROM 3 TO 4 ATOMS OF PHOSPHORUS PER MOLECULE, SAID PHOSPHONITRILIC HALIDE BEING PRESENT IN AMOUNT SUCH THAT THE PHOSPHORUSTO-LEAD ATOM RATIO IS FROM ABOUT 0.0067 TO ABOUT 0.67. 